DEREK B. COVINGTON, M.D.

RESIDENT PHYSICIAN – PGY2DEPARTMENT OF ANESTHESIOLOGY

UNIVERSITY OF MIAMI/JACKSON MEMORIAL HOSPITAL

Modification of Individual Diving Practices After PFO Diagnosis or PFO Closure

Background

Patent foramen ovale (PFO) is associated with an increased incidence of DCS1

Relative risk of divers with a large PFO is 4-6x greater than the overall risk of DCS in recreational scuba divers, which is 2 in 10,000 dives or 0.02% 2,3

Background

Risk lowering strategies include: No diving

More conservative diving Less frequent diving, limiting depth and/or bottom time,

or utilizing oxygen enriched breathing mixtures (i.e. Nitrox)

Surgical closure of PFO Complication risk of 1-2%

Complications include palpitations, bleeding, thrombosis, infection, perforation/erosion, and device embolization4

Background

Diving practices after diagnosis of a PFO in those who undergo closure and those who opt for non-surgical management has yet to clearly be defined

PFO

http://emedicine.medscape.com/article/156863-overview

Aim

To elucidate changes in diving practice by divers who are diagnosed with a PFO and choose to undergo closure and those divers diagnosed with PFO who choose non-surgical management

Methods

In 2010, Divers Alert Network (DAN) initiated study to assess risk-benefits of PFO closure in divers Inclusion criteria

18 years old or greater Certified Diver Diagnosis of PFO with medical clearance to dive

In 2012, we administered a follow-up survey to the enrolled 58 patients

Methods

2012 Survey Inquired

Number of dives Dive depths Breathing gases Possible complications of PFO closure DCS Symptoms General health status

Methods

Methods

Mean number of annual dives before PFO diagnosis and before closure were compared to diving practices after diagnosis (PFO group) or after closure (Closure group)

Difference in mean annual number of dives between the two groups was tested for statistical significance with an unpaired t-test

Results

Frequency of Diving

Table 1: Mean (St. Dev) annual number of dives before diagnosis and after diagnosis (PFO group) and before closure and after closure (Closure group)Group Before

Dx or Closur

e

After Dx or Closur

e

T-testP-

Value

PFO 46(36) 33(30) 0.95 0.35

Closure 43(33) 33(43) 0.88 0.38

Results

Frequency of Diving

Table 2: Number of divers who changed their frequency of diving

Group No diving

Less Dives

More Dives

PFO 3 6 3

Closure 8 10 6

ResultsComplications of Closure Table 3: Mean (St. Dev.) annual number of

dives before and after PFO closure in divers with and without complications

Outcome of Closure

Mean (St Dev.) Before

Mean (St. Dev) After

Complications*(n = 3)

8(4) 0(0)

No complications

(n = 21)48(32) 38(44)

* Two PFO were not fully closed. One diver reports recurrent visual symptoms.

Results

Decompression Sickness

Transient skin rash c/w Type I DCS PFO Group: 1 diver Closure Group: 2 divers

Transient bilateral LE paraesthesias c/w neurological or Type II DCS PFO group: 0 divers Closure group : 1 diver

© 2005 Netter Illustrations used with permission of Icon Learning Systems, a division of MediMedia USA, Inc. All rights reserved. http://www.usciences.edu/museum/netter_detail1.htm

Conclusions

No statistical difference between the mean annual dives of the PFO group and the Closure group following diagnosis and closure, respectively, was detected

Divers with uncomplicated closures did more dives afterwards, while those with closure complications, recurrent symptoms, or requiring medical clearance did less dives

Conclusions

Divers with PFO, who chose non-surgical management and did more dives than before diagnosis, used more oxygen-enriched breathing mixtures and limited their depth and time

Limitations

Number of enrolled divers May fail to reveal differences in diving practices

between those undergoing closure and those choosing non-surgical management

Lack of long-term follow-up May mask long-term improvements in diving

symptomatology in those who are currently experiencing acute and sub-acute complications from closure, not diving secondary to health concerns other than PFO, and lacking post-surgical medical clearance for diving secondary to health care access or time conflicts at the time of this analysis

Acknowledgements

Petar Denoble, M.D. Senior Research Director at Divers Alert Network

(DAN)

Doug Ebersole, M.D. Interventional cardiologist at the Watson Clinic Center

for Research

References

1. Sivertsen W, Risberg J, Norgard G. Patent foramen ovale and decompression illness in divers. JNMA. 2010 Apr 22; 130(8):834-8.

2. Lairez O. Risk of neurological decompression sickness in diver with right-to-left shunt: literature review and meta-analysis. Clinical Journal of Sport Medicine. 2009; 19(3): 231-5.

3. Germonpre P. Patent foramen ovale and diving. Cardiol Clin. 2005 Feb;23(1): 97-104.

4. Abaci A. Short and long term complications of device closure of atrial septal defect and patent foramen ovale: meta-analysis of 28,142 patients from 203 studies. Catheter Cardiovasc Interv. 2013 Feb 14 (Epub ahead of print)

Contact Information

Derek B. Covington, M.D.

Resident Physician – PGY2 Department of Anesthesiology and Perioperative

Medicine University of Miami Miller School of Medicine/Jackson

Memorial Hospital C: 305-301-9115 E: dcovington@med.miami.edu